This year's Big Garden Birdwatch, which took place in January, involved a record 552,000 participants across the UK, who logged garden visits by 8.5m birds of 73 different species. It is the largest mass-participation wildlife survey anywhere in the world.

As in previous years, house sparrows and starlings were the two most populous species in gardens. The RSPB warned, however, that their high position concealed the fact both species have suffered major declines since the survey first began in 1979. House sparrow numbers have fallen by 63% since the first survey, and starling numbers have dropped by 79%. This year's survey did bring one small sign of hope, with house sparrow numbers rising slightly, up almost 3% on 2008.

"There's no longer much food in the countryside for sparrows and starlings, so they come into our towns where our new houses are virtually impenetrable and insect numbers are down because of pollution," BBC Springwatch presenter Chris Packham said, adding that the species' long-term decline is not irreversible.

The big surprise this year was the long-tailed tit, rising from 14th to 10th place with numbers up 89% on 2008. At 14cm long, and weighing little more than a 50p coin, the long-tailed tit suffers badly from freezing weather. From the late 1970s to the mid-1980s a series of bitter winters caused the population to plummet, but a long run of mild winters has brought the species into the top 10 garden birds for the first time.

"A few years ago this bird wouldn't often have been seen on feeders, preferring instead to forage in the countryside," said Dr Mark Avery, the RSPB's director of conservation. "As more of us stock our feeders this little bird realises what we have to offer, and it's yet another beautiful bird we can enjoy from our windows."

Packham also praised the rising popularity of bird-feeding. "The great thing about this birdwatch is that not only are we engaging with half a million people, but the vast majority have put out feed for birds. From ubergeeks like myself to old ladies, people are making a difference to bird populations," said Packham.

Long-tailed tits were not the only surprise from this year's survey, with many respondents in the east of England enjoying sightings of waxwings, a scarce and irregular winter visitor from Scandinavia. The waxwing leapt 13 places up the bird-spotting chart, which the RSPB's Big Garden Birdwatch coordinator Sarah Kelly attributed partly to gardens with berry-bearing shrubs.

A change in what we feed birds is also said to be causing a greater diversity of species. "Gone are the days when all that was available was a bag of peanuts – as we become more aware of the different types of food suitable for garden birds, we are reaping the benefits with even more species on our tables and feeders than ever," said Avery.

The survey follows a recent report by Durham University, which said that climate change is leaving some native British birds facing extinction. Experts warn that changes in the British climate such as milder winters and drier summers could leave some species struggling to adapt. "Drier weather and sudden flooding in summer will affect inveterbrates including worms in the soil, which will in turn affect birds such as songthrushes, starlings and blackbirds," said Peter Brash, an ecologist for the National Trust. "I also hope that we'll see gardeners keep hold of lawns by picking drought-resistant varieties of grass rather than tarmacing over them because of higher temperatures."

Ecologists note that a warmer climate will, however, be good news for some bird species. "We would expect changes in the relative abundance of some of our common birds as climates warm across the UK and Europe, with some species increasing and some decreasing in abundance," said Dr Stephen Willis, lecturer in ecology at Durham University. "We project that the collared dove and goldfinch, both now common UK garden birds, should be doing better across Europe as the climate changes."